The effect of prosthesis patient mismatch after mitral valve replacement on postoperative pulmonary arterial pressure evaluated with echocardiography

Abstract:Introduction: There is still no consensus on the prevalance, definition , evaluation and clinical implications of prosthesis-patient mismatch (PPM) after mitral valve replacement (MVR) surgery and most issues remain controversial. Clinical and hemodynamic effects of PPM on mitral location could not be discovered wholly. However, PPM on mitral location is supposed to cause persistant pulmonary hypertension (PHT) and to prove useful as a crucial indicator of ongoing PHT after MVR.Objectives: In our study we aimed mainly to investigate the prevalance and effects of PPM on mitral location on postoperative pulmonary artery pressure (PAP) in patients with preserved left `ventricular function , and also to find out any correlation between `index effective orifice area? (IEOA), postoperative `systolic pulmonary artery pressures? (SPAP) and other hemodynamic parameters.Materials and Method: 100 patients with normal functioning prosthesis mitral valves were enrolled to our study. They were from 26 to 84 years of age (mean 51.1 ± 11.5 years) and their PAP measurements had been performed via echocardiographic study before MVR procedure. 27 of patients (27%) were male and 73 (73%) were female. Mean follow-up period with echocardiography was 35 months. `Prosthesis mitral effective orifice area?(PMEOA) was calculated using continuity equation in echocardiography . PMEOA divided by `body surface area? (BSA) was equal to IEOA and PPM was defined as presence of an IEOA value ? 1,2 cm2/m2. Both groups with or without postoperative PPM were evaluated and compared to each other in terms of their general demographic features and degree of postoperative SPAP, statistically. PHT was defined as SPAP ? 40 mmHg.Results: 33 (33%) of 100 patients recruited to our study were categorized to the PPM (+) group and PHT was detected in 31 patients (31%). In the PPM (+) group, postoperative mean SPAP was 42.0±6.6 mmHg and rate of PHT; 79%, whereas in the PPM (-) group postoperative mean SPAP was 29.9±6.0 mmHg and rate of PHT; 8% (p<0.001). Postoperative decrease of SPAP in the PPM(+) group was lower with a statistical significance compared to that of PPM(-) group (p<0.001). A negative correlation of moderate degree was revealed between SPAP and IEOA values (r= - 0.53, p<0.001). On the other hand, no correlation was found between valve number, IEOA and SPAP. In the multivariate analysis, IEOA was determined to be one of the most important independent variables affecting postoperative SPAP and most important predictor of PHT.Conclusion: Persistant PHT was noted to occur frequently after MVR operation and have an association with PPM. Presence of PPM or low IEOA, in other words, was shown to be closely related to the decrease of SPAP and frequency of PHT after the operation. Our study pointed out that implantation of prosthetic valves compatible with careful preoperative echocardiographic measurements and BSA may prevent PPM and therefore provide a relative improvement in PHT.